It is known in the prior art to determine the distance between an object and a vehicle by illuminating the object with an infrared pulse, and measuring the time required for a reflection pulse to return to an infrared receiver from the object.
Because the distance of the object from the vehicle is not precisely known before the receipt of the reflected pulse, detection of the reflection pulse typically requires sampling the output of the infrared receiver at a variety of distinct times and identifying which sample (if any) has an amplitude that indicates receipt of at least a portion of a reflected infrared pulse. Further, the reflected pulse may be distorted and spread out over time, such that portions of the reflection may be captured by several samples, and the difference in amplitude from one sample to the next may be small. Sampling such signals with an analog-to-digital converter would require a very fast, high resolution analog-to-digital converter.